A working guide to forensic evidence in criminal cases, written for the lawyer who has to decide where to spend a limited budget. Part one covers how these disciplines entered evidence law and why precedent substituted for validation. Part two sorts the disciplines by what they can actually support. Part three covers the admissibility framework and the scope motion that outperforms the exclusion motion. Part four covers DNA, mixtures, transfer, and proprietary interpretation software. Part five covers the confrontation line from Crawford through Smith v. Arizona and the notice-and-demand deadlines that waive it. Part six covers laboratory disclosure obligations and the scandal pattern. Part seven covers cognitive bias and the controls that address it. Part eight covers cross-examination, experts, and post-conviction relief.